Film-forming cosmetic compositions and especially nail varnish compositions should have a certain number of characteristics allowing their application and good durability on the support.
Cosmetic compositions in particular preferably show good applicability and good covering power; good adhesion to the support (surface of the nail, or the hair); a certain amount of flexibility and good strength of the film in order to avoid cracking and chipping in the case of varnishes; the possibility of obtaining a glossy uniform film.
In the field of nail varnishes, the main film-forming material used at the present time is a film-forming resin known as a “primary resin”, which is generally nitrocellulose. It is also possible to totally or partly replace it with a polyvinyl resin such as polyvinyl butyrate or alternatively with cellulose acetobutyrate or acetopropionate.
To impart good adhesion, and thus to ensure good durability, secondary resins of different nature are also used, such as arylsulfonamide-formaldehyde or arylsulfonamide-epoxy resins, polyester resins, resins of alkyd type, polyurethane resins, polyester-polyurethane resins, polyether-polyurethane resins, and vinyl and/or acrylic resins, alone or as a mixture.
These secondary resins make it possible to increase the film-forming power of nitrocellulose and improve the gloss and also the adhesion of the films.
Moreover, to adjust the flexibility of the film without weakening its physical strength, plasticizers are used, for instance phthalates or citrates.
In order to improve the durability of the film and its resistance to chipping, various secondary resins, especially of modified alkyd type, have been proposed. Mention may be made in particular of document FR 2 562 793, which describes the use of sucrose benzoate in combination with resins of toluenesulfonamide-formaldehyde type; or document JP-61-246 113, which describes the use of sucrose benzoate in combination with a glycidyl versatate ester-modified alkyd resin. Mention may also be made of WO 2002/243 676, which describes the use of a neopentyl glycol trimellitate adipate polyester resin in combination with alkyl acrylate and methacrylate copolymers.
JP-58-023 614 is also known, which describes the use of modified polyester obtained by condensation of pentaerythritol with cis-4-cyclohexene-1,2-dicarboxylic acid and castor oil fatty acids, followed by reaction with a dioxirane compound of epoxy resin type; or alternatively JP-54-011 244, which describes the use of a modified polyester obtained by condensation of dipentaerythritol with cyclohexane-1,2-dicarboxylic acid and castor oil fatty acids, followed by reaction with a dioxirane compound of epoxy resin type.
However, although these combinations significantly improve the durability, they are still considered insufficient in terms of long durability.